Signal Transduction System of Experimentally Induced Cholesteatoma in the Mongolian Gerbil

Lee, Dong Hoon; Park, Kee Hyun; Park, Hong Joon; Chun, Jeong Min; Hwang, Sung Chul

Abstract

BACKGROUND AND OBJECTIVES: Hyperproliferative character of the cholesteatoma in the middle ear seems to be related to epithelial cell proliferation and differentiation. The proliferation of cells, their differentiation and organization in specialized tissues and the expression of their differentiated properties are under control of a large number of regulatory processes and complex interactions called signal transduction. PLC-gamma1 is a substrate of protein kinase located in EGFR, PDGFR-alpha and -beta and signal transduction through PLC-gamma1 participates in the regulation of cell growth and differentiation. This study was undertaken to investigate the distribution of PLC-gamma1, EGFR and PDGFR in experimentally induced cholesteatoma, deep meatal skin and retroauricular skin of Mongolian gerbil.
MATERIALS AND METHODS
Using Western blotting and immunohistochemical techniques, we investigated the reaction patterns of antibody to PLC-gamma1, EGFR, PDGFR-alpha and PDGFR-beta as a proliferation and differentiation marker in the experimentally induced cholesteatoma matrices of Mongolian gerbil. For the control, same study was performed with deep meatal skin and retrosuricular skin.
RESULTS
By Western blotting, considerably higher levels of PLC-gamma1, EGFR protein were detectable in cholesteatoma compared with control, however, PDGFR-alpha and -beta were not detected in cholesteatoma The immunostaining intensity of PLC-gamma1 and EGFR at suprabasal cell layer and basal cell layer were intense in cholesteatoma than in control. PDGFR-alpha and -beta were not detected in both cholestatoma and control.
CONCLUSION
Over-expression of PLC-gamma1 and EGFR in induced cholesteatomas may contribute abnormal proliferation and differentiation of their epithelial cell. Authors suggest that induced cholesteatoma in Mongolian gerbils can be a good model of signal transduction study for cholesteatoma.